There are four songs in the poem. Three of which are headed by the
Latin ‘Canticus ...’. The reason that the fourth, Antigone’s song, does
not have such a title, may have to do with the fact that Chaucer had no
direct source for this song, and thus didn’t feel that he needed to
credit it.

* Antigone's song is original to
Chaucer. The Canticus is probably scribal.

Song 1
Book I, ll. 400 - 420 .
Sung by Troilus.
Source:
Fairly close rendering of Petrarch’s Sonnet 88 (In Vita), no. 132 in
the Canzoniere, “S’amor non e”, in form released by Petrarch after 1359.
This translates as ‘if this be not love’.
Variations between the Petrarchan sonnet and Chaucer’s version may have
resulted from Chaucer misunderstanding the Italian.
ll. 400 - 406: became part of a 15th century moral treatise for
religious women.
l. 411: the oxymoron ‘quike deth’ has been considered a distinguished
Petrarchan amorous lyric, though it is common in earlier poetry.
l. 416: image of ship without rudder was proverbial. It appears again
in the Proem to Book II, in which the boat represents the Church.

This is Troilus’ vocalisation of his feelings immediately after falling
in love with Criseyde, and before Pandarus comes into the picture.
It is clear that he is overwhelmed and not able to understand / deal
with the situation.
This is paradoxical: in describing his love as a ‘wondre maladie’ (l.
419), the love is at once made a burden / affliction; negative
connotations which are to persevere.

Song 2
Book II, ll. 827 - 875.
Sung by Antigone.
Chaucer’s own creation.
l. 867: first appearance in English of the proverb ‘people in glass
houses shouldn’t throw stones’. Came from the Italian.

Coming soon after Criseyde sees Troilus from her window, Antigone’s
song plays a big part in influencing her feelings towards him.
The song emphasises the humility of love.
By calling those that would criticise love as a ‘thraldom’ (l. 856),
‘envyous’ (l. 857), the song gets right to the heart of Criseyde’s
thoughts.

Song 3
Book III, ll. 1744 - 1771.
Sung by Troilus.
Source:
Poem by Boethius (2m.8).
Chaucer substituted this for the song used by Boccacio at this point
(this was because Chaucer had already used the material of Boccacio’s
song for the Proem of Book III; Boccacio’s own Proem had come from the
Boethius, and this is what Chaucer returns to).
One critic interpreted Boethius’s poem as addressing ‘divine love’.
l. 1762 - 1768: adapted from Dante’s address to the Virgin Mary,
Paradiso : 33.14-18, especially verse 15: “sua disianza vuol volar
sanz’ ali”.
This translates as ‘his desire wishes to fly without wings’.
In a similar way to the sentiment of Antigone’s song, the Dante
emphasises the potential for the image of ‘bonds’ within love to be
positive.

This song comes at the height of Troilus’ happiness, and is his
celebration of it.
Positioned at the end of Book III, it contrasts heavily with the
beginning of Book IV (and the beginning of Troilus’ end), particularly
with Troilus appeal that God might make everyone in love: ‘from his
bond no wight the wey out wiste’ (l. 1768).
Book III is framed by hymns to love. Attention is drawn to this
particularly by Chaucer’s rearranging of the source material, but
Boccacio had done the same thing compositionally.

Song 4
Book V, ll. 638 - 644.
Sung by Troilus.
Source:
Taken from the Filostrato.
The Chaucerian image of a voyage may come from a misinterpretation of
the Italian.
l. 644: ‘Caribdis’ - legendary whirlpool.

The last and shortest song comes after Troilus’ return from visiting
Sarpedon, and with the failure of Pandarus’ attempts to distract him.
He still retains some hope for ‘the tenthe nyght’, but a final despair
and submission seem to be gathering.